Mock-up experiment at Birmingham University for BNCT project of Osaka University – Neutron flux measurement with gold foil

Tamaki, Shunsuke; Sakai, Makoto; Yoshihashi, Sachiko; Manabe, Masanobu; Zushi, Naoki; Murata, Isao; Hoashi, Eiji; Kato, Ikunoshin; Kuri, Shuhei; Oshiro, S.; Nagasaki, Masayuki; Horiike, Hiroshi

doi:10.1016/j.apradiso.2015.07.037

Cited by 8 publications

(4 citation statements)

References 2 publications

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“…The neutron moderator assembly used in the 1mA test was designed basing on various experiences of neutronic experiments at OKTAVIAN neutron source facility, and consisted of planer Li layer surrounded by cylindrical graphite reflector and dual component moderator of 20cm in diam. The detailed configuration and results are shown in papers [5][6][7]. The data report neutron flux and -ray distribution on the bottom surface of the assembly, that is, on the patient-side surface of the wall.…”

Section: Neutron Moderator Assemblymentioning

confidence: 99%

Liquid Li based neutron source for BNCT and science application

Horiike

Murata

Iida

et al. 2015

Applied Radiation and Isotopes

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Section: Neutron Moderator Assemblymentioning

confidence: 99%

Liquid Li based neutron source for BNCT and science application

Horiike

Murata

Iida

et al. 2015

Applied Radiation and Isotopes

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“…The most common method is the use of a gold wire. Here, the gold wire is set in water and then the radioactivity of the wires is measured with a radiation detector, such as a semiconductor detector, after irradiation of the neutron beam [3]. Since this is a reliable method to determine the neutron distribution, it is now the most commonly used method for QA of neutron beams in BNCT facilities.…”

Section: Introductionmentioning

confidence: 99%

Imaging of gamma photons from activated gold wire using a high-energy gamma camera after irradiation of neutrons from boron neutron capture therapy (BNCT) system

Yamamoto

Kataoka

et al. 2023

J. Inst.

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Gold wire is commonly used for quality assurance (QA) of the neutron beam in a boron neutron capture therapy (BNCT) system. It is set in water and irradiated with the neutron beam, and then 412-keV gamma photons from the activated gold wire are measured by a semiconductor detector. Since this procedure takes time and labor, a more efficient method is desired. To reduce the time and labor to measure the radioactivity of an activated gold wire, we carried out imaging of 412-keV gamma photons from the activated gold wire using a developed high-energy gamma camera. After the gold wire was set in the depth direction in a water-filled phantom and irradiated with neutron beams using the BNCT system, gamma photon imaging was conducted with the developed high-energy gamma camera. On the measured image, a depth profile was set to obtain the neutron distribution, and this was compared with the profile sequentially measured with a semiconductor detector. An image of the 412-keV gamma photons was obtained with an imaging time of 1.5 hours. The estimated depth profile of the neutron beam from the gamma camera image closely matched that measured with a semiconductor detector. Imaging of the gamma photons emitted from the activated gold wire was possible, and it offers an efficient method to measure the thermal neutron distribution of the BNCT system. This method has the potential to reduce the time and labor for QA of a BNCT system.

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“…One method is to position gold foil wires at different depths in water and then measure the radioactivity of the foil after irradiation of neutrons to estimate the thermal neutron distribution. 3 This is a reliable method to determine the thermal neutron distribution, but the need to measure radioactivity in gold is timeand labor-consuming. Another method adopts an optical fiber-based detector using a neutron-sensitive scintillator to measure the thermal neutron distribution.…”

Section: Introductionmentioning

confidence: 99%

“…However, it is difficult to measure the dose distribution in water. One method is to position gold foil wires at different depths in water and then measure the radioactivity of the foil after irradiation of neutrons to estimate the thermal neutron distribution 3 . This is a reliable method to determine the thermal neutron distribution, but the need to measure radioactivity in gold is time‐ and labor‐consuming.…”

Section: Introductionmentioning

confidence: 99%

Technical note: Optical imaging of lithium‐containing zinc sulfate plate in water during irradiation of neutrons from boron neutron capture therapy (BNCT) system

Yamamoto

Yabe

et al. 2022

Medical Physics

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Purpose Optical imaging of ionizing radiation is a possible method for dose distribution measurements. However, it is not clear whether the imaging method is also applicable to neutrons. To clarify this, we performed the imaging of neutrons in water from boron neutron capture therapy (BNCT) systems. Such systems require efficient distribution measurements of neutrons for quality assessment (QA) of the beams. Method A water‐filled phantom was irradiated from the side with an epithermal neutron beam, in which a lithium‐containing zinc sulfate (Li‐ZnS(Ag)) plate was set in the beam direction, and during this irradiation the scintillation of the plate was imaged using a cooled charge‐coupled device (CCD) camera. In the imaging, Li‐6 in the Li‐ZnS(Ag) plate captures neutrons and converts them to alpha particles (He‐4) and tritium (H‐3), while ZnS(Ag) in the Li‐ZnS(Ag) plate produces scintillation light in the plate. We also conducted Monte Carlo simulation and compared its results with the experimental results. Results The image of the emitted light from the Li‐ZnS(Ag) plate was clearly obtained with an imaging time of 0.5 s. The depth and lateral profiles of the measured image using the Li‐ZnS(Ag) plate showed the same shapes as the neutron distributions measured with gold foil, within a difference of 8%. The destructive effect of neutrons on the CCD camera increased approximately three times, but the unit was still working after the measurement. Conclusion The optical imaging of neutrons in water is possible, and it has the potential to be a new method for efficient QA as well as for research on neutrons.

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Mock-up experiment at Birmingham University for BNCT project of Osaka University – Neutron flux measurement with gold foil

Cited by 8 publications

References 2 publications

Liquid Li based neutron source for BNCT and science application

Liquid Li based neutron source for BNCT and science application

Imaging of gamma photons from activated gold wire using a high-energy gamma camera after irradiation of neutrons from boron neutron capture therapy (BNCT) system

Technical note: Optical imaging of lithium‐containing zinc sulfate plate in water during irradiation of neutrons from boron neutron capture therapy (BNCT) system

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